STUART, Fla. (AP) — FBI tests showed that the Florida college student accused of randomly killing a couple and chewing on the dead man’s face had no detectable hallucinogenic drugs in his system.

According to a report released Wednesday, 19-year-old Austin Harrouff did have alcohol and trace amounts of marijuana in his system after his arrest for allegedly killing 59-year-old John Stevens and his 53-year-old wife, Michelle Mishcon, outside their Tequesta-area home Aug. 15.

Harrouff allegedly told deputies minutes after the slayings that they would find no drugs in his system, but he had suffered a burned esophagus, possibly from ingesting chemicals found in the couple’s garage.

Harrouff’s attorney, Nellie King, said in a statement that her client is mentally ill.